1. Field of the Invention
This invention relates to novel polycyclic aromatic group-pendant polysilanes which have utility as photoconductive and electrically conductive materials and are particularly useful in the fields of electrodes for batteries, solar cells, boxes for electromagnetic shields and the like, and also to conductive polymers obtained by doping such polysilanes.
2. Description of the Prior Art
In recent years, it has been found that doping of polyacetylene with electron acceptors or electron donors results in a charge transfer forming reaction, thereby developing high electric conductivity based on the electron conduction. Attention has now been paid to conductive organic polymer compounds such as polyacetylene, polyphenylene, polypyrrole, polyaniline and polythiophene for use as materials capable of forming highly conductive films.
However, these organic polymer compounds are not molten or fused and are poor in shaping properties. Accordingly, the following problems are involved. Where these polymers are formed into films according to a vapor phase polymerization process or an electrolytic polymerization process, limitation is inevitably placed on the shape of the resultant film, which depends on the shape of a reactor container or an electrode. In addition, when doped with electron acceptors or electron donors, the polymers suffer considerable degradation, thus presenting problems with practical applications.
On the other hand, known polysilanes are predominantly made of those polysilanes which have, as substituents, an alkyl group typical of which is a methyl group, and a phenyl group (R. West et al., J. Am. Chem. Soc. 103, 7352 (1981)).
Also, there have been prepared polysilanes which have hydrogen or reactive carbon-carbon double bonds as a substituent or which have halogenated alkyl groups. This enables one to crosslink the polysilanes, with increasing expectations of their applications (R. West et al., J. Organomet. Chem., 300, 327 (1986)).
Very recently, there have been proposed applications, to resist materials, of polysilanes into which silyl groups are introduced (Japanese Laid-open Patent Application No. 63 -12636 or U.S. Pat. No. 4,727,120) and polysiloxanes introduced with phenolic substituents (Japanese Laid-open Patent Application No. 63-113021 or U.S. Pat. Nos. 4,822,716, 5,017,453 and 5,198,520).
Polysilanes contain silicon atoms, so that they are more metallic in nature and exhibit greater non-electron-localizing properties than those compounds made of carbon atoms. In addition, polysilanes are highly resistant to heat, are flexible and have good thin film-forming properties, thus being very interesting polymers. However, few polysilanes have been known as having high conductivity, with the exception of West el al's polysilastyrenes which are doped with fluorine compounds such as SbF.sub.5, AsF.sub.5 and the like, thereby obtaining highly conductive polymer materials (R. West et al, J. Am. Chem. Soc., 103, 7352 (1981)). However, there is a demand for conductive polysilanes which exhibit high electric conductivity and which are obtained conveniently from the standpoint of industry.